By Gary Raham,
Nature Writer & Illustrator
In 2006, people first noticed a cold-adapted fungus, now known as Geomyces destructans, growing on the snouts and wings of hibernating bats in the caves of eastern New York State. The condition became known as White-Nose Syndrome, or WNS. The fungus assault arouses bats from slumber, causing them to burn fat reserves and perish before spring. The mortality rate is typically 90 to 100 percent in little brown bats, a commonly victimized species. Over a million bats are believed to have died in eastern states.
Although there are no confirmed cases in Colorado, ecologists and bat biologists worry that the plague will spread and continue to impact these critically important flying mammals.
Critically important? Absolutely. Bats may perform their ecological chores in the dark, serve as extras in horror movies, and look downright ugly, but they work hard gobbling up insects and getting involved in the sex life of plants.
The number of bat species serves as a measure of their importance. If we could line up the more than 5,000 species of mammals in the world, 1,100 of them would be bats, according to bat ecologist Phil Richardson.
Bats evolved sometime late in the age of dinosaurs, when flowering plants began blossoming in the understories of evergreen forests and flirting with insects and other species, enticing them to aid in pollen and seed dispersal. Bat diversification undoubtedly took off after an asteroid collided with Earth 65 million years ago, destroying the ecologies of the Mesozoic world and providing expansion opportunities for fast-growing flowering plants, their insect partners, and hot-blooded, tiny, mammalian furry things with no more reptilian overlords.
In modern North America most bat species specialize in munching on insects. The little brown bat so decimated by G. destructans consumes about 600 mosquitoes per hour, according to the Colorado Bat Society (http://www.coloradobats.org/about.html).
Bat society founder and president Rick Adams says they are “the only serious nighttime foragers on mosquitoes and many species of agricultural pests that cause millions of dollars of damage each year.”
In the desert southwest and other parts of the world, various bat species serve as critically important pollinators for many plant species.
Although scientists have been able to track the development and spread of white-nose syndrome in eastern caves, bat biologists know far less about the hibernating habits of western bats. The Bureau of Land Management (BLM) admits to ignorance about much of bat biology. “We have limited knowledge of where bats roost in Colorado,” the agency says on their website. “Roosts in caves and mines with moist, cool conditions are of highest risk for WNS.”
The BLM has about 3,200 mines on their Abandoned Mine Lands (AML) database and is in the process of surveying an estimated 20 known cave sites.
G. destructans spreads from bat to bat. Most likely, humans can also spread the fungus through contamination of clothing and equipment used in cave exploration. For this reason, and because a bat was found infected with G. destructans in an Oklahoma cave, all caves in Colorado are closed at least until July 27, 2011, as mandated by the United States Forest Service. More information about the Colorado Cave Survey — an elected body of cavers who serve as a liaison between the Colorado caving community and various land management agencies — is available at http://www.coloradocavesurvey.org/. Cavers can also find information about proper cleaning of equipment at this site.
The U.S. Fish & Wildlife Service urges people to be on the lookout for bats that may be victims of WNS. The white fungus on a bat’s nose provides a key clue, of course, but bats flying outside during the day in temperatures at or below freezing is another sign of disturbed hibernation. Naturalists should also look for bats clustered near the entrance of hibernating sites and for dead and dying bats on the ground or other places.
Because bats can also come down with rabies and pass that disease to humans, people should be very careful handling or disposing of bats. The Colorado Division of Wildlife site provides both submission protocols for WNS reports and safety tips (http://wildlife.state.co.us/Research/WildlifeHealth/WNS).
The humorist Will Cuppy once wrote, “In order to love bats one has to be terribly fond of Nature.” One doesn’t have to love bats to appreciate their importance in nature’s complex ecosystems, but it’s not too terribly hard to love a furry flyer that keeps all those summer mosquitoes on the run.